People with the solar company "Sungevity", take turns running under a parachute globe they brought along, as they joined hundreds for a parade and rally for "Moving Planet" demanding solutions to climate change, peace and sustainability, in San Francisco, Ca., on Saturday September 24, 2011.

Photo: Michael Macor, The Chronicle

People with the solar company "Sungevity", take turns running under...

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Hundreds joined a parade for "Moving Planet" demanding solutions to climate change, peace and Sustainability, as they moved up Market St. in San Francisco, Ca., on Saturday September 24, 2011, ending at Civic Center Plaza in front of City Hall.

Photo: Michael Macor, The Chronicle

Hundreds joined a parade for "Moving Planet" demanding solutions to...

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Christine Holmes, of San Francisco, with the Center for Biological Diversity, showed her support for the Bluefin Tuna, as she joined hundreds in a parade and rally for "Moving Planet" demanding solutions to climate change, peace and sustainability, in San Francisco, Ca., on Saturday September 24, 2011.

Photo: Michael Macor, The Chronicle

Christine Holmes, of San Francisco, with the Center for Biological...

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"Grandmother Earth" with the Oakland group, "Bay Localize", joined hundreds in a parade and rally for "Moving Planet" demanding solutions to climate change, peace and Sustainability, as they moved up Market St. in San Francisco, Ca., on Saturday September 24, 2011.

Photo: Michael Macor, The Chronicle

"Grandmother Earth" with the Oakland group, "Bay Localize", joined...

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Bike riders showed their support for clean transportation as they joined hundreds in a parade and rally for "Moving Planet" demanding solutions to climate change, peace and sustainability, as they moved up Market St. in San Francisco, Ca., on Saturday September 24, 2011.

Photo: Michael Macor, The Chronicle

Bike riders showed their support for clean transportation as they...

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"Grandmother Earth" with the Oakland group, "Bay Localize", joined hundreds in a parade and rally for "Moving Planet" demanding solutions to climate change, peace and sustainability, as they moved up Market St. in San Francisco, Ca., on Saturday September 24, 2011.

Photo: Michael Macor, The Chronicle

"Grandmother Earth" with the Oakland group, "Bay Localize", joined...

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Colin Miller, with the Oakland group, "Bay Localize", joined hundreds in a parade and rally for "Moving Planet" demanding solutions to climate change, peace and sustainability, as they moved up Market St. in San Francisco, Ca., on Saturday September 24, 2011.

Photo: Michael Macor, The Chronicle

Colin Miller, with the Oakland group, "Bay Localize", joined...

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6-year-old, Philip Barr of Oakland, picks out a sign to carry as he joined hundreds for a parade and rally for "Moving Planet" demanding solutions to climate change, peace and sustainability in San Francisco, Ca., on Saturday September 24, 2011.

Photo: Michael Macor, The Chronicle

6-year-old, Philip Barr of Oakland, picks out a sign to carry as he...

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Tyler Cullen, 12-years-old, of Marin County,with cooltheearth.org joined supporters gathered for a rally in front of City Hall for "Moving Planet" demanding solutions to climate change, peace and sustainability, in San Francisco, Ca., on Saturday September 24, 2011. Cool The Earth is a free, ready-to-run climate change assembly program that educates K-8 students and their families about climate change and inspires them to take simple actions to reduce their carbon emissions.

Photo: Michael Macor, The Chronicle

Tyler Cullen, 12-years-old, of Marin County,with cooltheearth.org...

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A Polar Bear with the Center for Biological Diversity was among the supporters gathered for a rally in front of City Hall for "Moving Planet" demanding solutions to climate change, peace and sustainability, in San Francisco, Ca., on Saturday September 24, 2011.

Photo: Michael Macor, The Chronicle

A Polar Bear with the Center for Biological Diversity was among the...

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Mike Haines, of San Rafael joined supporters gathered for a rally in front of City Hall for "Moving Planet" demanding solutions to climate change, peace and sustainability, in San Francisco, Ca., on Saturday September 24, 2011.

San Francisco -- With shouts demanding an end to fossil fuels, hundreds of people marched, biked and scooted down Market Street on Saturday as part of a global Moving Planet day.

Some were dressed as polar bears and fish, while others carried signs calling for better public transit, more solar and wind energy, and cleaner air. Many participants took the opportunity to blast plans for a pipeline that would carry crude oil from the tar sands of western Canada into the United States. But everyone was there to express concern at the growing carbon dioxide levels in the atmosphere.

San Leandro teacher Maureen Forney was dressed as a red-legged frog, a species once ubiquitous in the Bay Area but now threatened. And San Francisco resident Jennifer Harris donned a polar bear hat to march with her 2-year-old daughter, Harper.

Having a young child makes the issue that much more urgent, she said.

"Having her made me realize even more how we need to take action now - it makes this more personal," Harris said. "And I want her to understand that in a democracy, part of our responsibility is to show up and say what we want from our government."

The San Francisco event was one of an estimated 2,000 taking place around the globe, all aimed at urging local leaders to work to move beyond fossil fuels and lower the amount of carbon dioxide in the atmosphere to 350 parts per million. Climate change experts and scientists believe that amount is the upper limit of what is safe; currently, the level is around 390 ppm.

Moving Planet aimed to adapt each event to local needs - and in the Bay Area, environmentalists chose to focus their efforts on pushing leaders to make use of a 2008 state law that calls for regions around the state to reduce greenhouse gas emissions through local strategies.

The Metropolitan Transportation Commission is responsible for creating that plan in the Bay Area, and organizers of Saturday's event said the only way to make those reductions is to find alternatives to driving.

"When you think about climate change, transportation is one of the biggest contributors - it's responsible for over one-third of greenhouse gas emissions," said Stephanie Reyes, policy director at the Greenbelt Alliance. "Most people think, 'Let's get more fuel-efficient cars.' ... But the other half of the solution is thinking about how much we drive our cars, whether they are fuel-efficient or not."

Regional leaders will have $244 billion to spend, said Aaron Lehmer of Bay Localize, an environmental group.

"Instead of more freeways, we need affordable home options in walkable, bikeable communities," Reyes said. "(Today) we're trying to get out and explain to residents that there is this opportunity."

Participants Amanda Ravenhill, 28, and Ryan Kushner, 33, said connecting the economy to the need for climate change solutions is critical. Both are recent graduates of the Presidio Graduate School's sustainable management program and were riding bikes with flags that read, "Economists agree - climate change is bad business. Ask me, I'm a MBA."

Ravenhill said she and Kushner are entrepreneurs and recently started their own environmentally conscious businesses.

"Our message is really more economic - it's about jobs. The next industrial revolution is building a cleaner economy," she said. "It's about everyone's future. There aren't winners and losers, we all win or we all lose."

The day was also a chance for a wide range of groups to bring their voices to the climate change debate. Among those participating were the California and Bay Area chapters of the National Organization for Women and the local Los Ecos Amigos, which focuses on connecting the Latino community with environmental resources.

"Environmental sustainability is paramount to women's empowerment," said Patty Bellasalma, president of California NOW. "It's tied up into so many other issues that affect women all over the world ... women are impacted whether it's what they are transmitting to their children through breast milk or worried about feeding their children."